Convicted con artist Bernie Madoff claims the pain felt by the thousands of investors he defrauded is "nothing" compared to the loss he feels after his two sons died.

The infamous Ponzi schemer made the startling revelation in a letter from behind bars to NBC News. The diatribe was directed towards Irving Picard, the trustee representing his small village of victims.

Sons Andrew died of cancer last September and Mark hanged himself in 2010 on the second anniversary of his father's arrest.

"As difficult as it is for me to live with the pain I have inflicted on so many," Madoff wrote, "there is nothing to compare with the degree of pain I endure with the loss of my son's Mark and Andy.

"I live with the knowledge that they never forgave me for betraying their love and trust," Madoff continued.

"The fact that I was trying to protect our family by sheltering them from any knowledge or involvement in my wrong doing still fails to allow me to forgive myself."

Bernie Madoff continued to argue in the letter that his sons had nothing to do with his $40 billion con.
"The Trustee claimed that my sons should have known that I was not executing any trades for my advisory clients," wrote the former Nasdaq head.

"The Trustee claimed that my sons should have known that their compensation was unrealistic."

Madoff continued: "I would remind everyone that the Trustee's civil litigation against my son's as directors of Madoff Securities International in London was not only DISMISSED, the judge lambasted the trustee for his baseless claims and unnecessary harassment of my son's."

Madoff will spend the rest of his life behind bars. Most of his victims will never fully recoup their losses.